Swype, the handy keyboard replacement that thrives on other platforms (most notably Android), has been ported to work on jailbroken iOS versions by Andrew Liu (a.k.a. wyndwarrior). You can get it by downloading from here, and then SSHing it to your device and installing through iFile.app. You can also add the following repo to Cydia and grab the install from there: wynd.x10.mx/repo
Andrew does warn that the package is still very much in a beta state, and that it won’t work in many apps (App Store apps being the most notable; he also mentions that a fix should be coming very soon).
After you install, be sure to respring! Make sure you’re following Andrew on Twitter to get the latest updates!
If you aren’t jailbroken, it’s now simpler than ever. Check it out here!